         serializable-data data]
     (set-world-print-method (:world-filename options))
     (miner.tagged/pr-tagged-record-on serializable-data writer)
-    (.toString writer)))
+    (str writer)))
 
 (defn world-reader [resolver]
   (fn [value]

    (fn [game group-id]
      (let [current-group (political-entity-at history t group-id)
            prev-group    (political-entity-at history prev-t group-id)]
        (if (not (nil? prev-group))
          (if (= :unchanged (.culture current-group))
            (let [updated-group (assoc current-group :culture  (.culture prev-group))]
              (update-political-entity game (.id updated-group) (fn [_ _] updated-group)))

    fress/inheritance-lookup))

(defn- fress-read-handlers [resolve]
  (fress/associative-lookup
    (merge
      {world-ftag (world-freader resolve),
       language-ftag (language-freader)}
      fress/clojure-read-handlers)))

(defn to-serialized-bytes [data]
  (let [os (java.io.ByteArrayOutputStream.)
